How to know if a tenant name is available or taken

[Juan Carlos González Martín]

If you need to know if a tenant name is available or taken in Office 365, I recommend to follow you one of the following approaches:

• First one is by using the following web page: http://o365.rocks/. There you will be able to do a quick check for the availability of a tenant name in Office 365.
• The other approach is just to use the PowerShell script you can find here: https://www.linkedin.com/pulse/how-check-office-365-tenant-name-availability-aaron-dinnage

Screenshots and original post here: https://jcgonzalezmartin.wordpress.com/2016/11/21/office-365-how-to-know-if-a-tenant-name-is-availab...

[#2]

Hi @Juan Carlos González Martín,

Isn't the easiest way just to go to http://requiredtenantname.sharepoint.com/ or  even better http://requiredtenantname-admin.sharepoint.com/ if you get a login then it's been taken.

if you get 

This site can’t be reached

then it is free.

[#3]

Interesting workaround, but I like the approaches suggested

[#4]

Looks like it does just that :)

[#5]

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@Pieter Veenstra wrote:

Isn't the easiest way just to go to http://requiredtenantname.sharepoint.com/ or  even better http://requiredtenantname-admin.sharepoint.com/ if you get a login then it's been taken.

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Great idea. But if the Tenant ist a Exchange Online only Tenant it will not work.

[#6]

Hi Joerg,

It can also start to do a Trial and see if the Tenant name is active.

Trial Link http://go.microsoft.com/fwlink/p/?LinkID=403802 

[#7]

@Juan Carlos González Martín The Powershell script options now returns an error. 

ErrorType=FunctionNotFoundException
ErrorCode=Unknown
PartnerServiceErrorCode=
CorrelationID=b5a8bxxx-xx52-4b8x-x2b7-4c1xxx6330e4

[#8]

Here's an related follow up query... do you know if there's any obvious way to CONTEST an already taken tenancy name?

Got a new O365 customer and there is no possible way the obvious tenancy name could have been taken legitimately (unless they previously signed up for a trial or such like and forgot the details, but they swear that's not the case), and it is already in use.
Any way to get Microsoft to query an existing tenancy to see whether it's actively in use, transfer ownership, send through login details etc.
Basically, the equivalent of domain hijacking resolution.